In Depth Coverage

Vegetation responses to climate change (Alaskan and later Siberian Arctic)

Changes in high latitude vegetation have become increasingly visible in the last decades. Shrubs now occur further north and at greater densities than just fifty years ago, and the growing season at high latitudes has become longer. Because the boreal biome forms the largest terrestrial carbon reservoir on earth, it is important to understand the implications of changes in these ecosystems and their feedbacks to the climate system.

Remote sensing studies have shown that the trends in vegetation productivity in recent decades differ remarkably between tundra and boreal forest vegetation. While productivity in the tundra has increased in most areas (“greening”), boreal forests have experienced reduced productivity (“browning”).

We propose to extend this analysis using high resolution remote-sensing data to refine the intensity of these changes and associate them with field observations, focusing on central and northern Alaska and on the Cherskii region of Russia, where dramatic changes in productivity and the fire disturbance regime have been documented by field research. We will inform ecosystem models with these data sets to better assess the implications of high latitude vegetation changes on carbon exchange under projected future climate scenarios, and work with local people to consider adaptation and mitigation strategies.

• Link With Climate Change

  Open

  Many recently observed changes in biological systems around the globe, particularly at high latitudes, have been shown to be responses to climate change. These responses are nowhere more directly, widely or dramatically evident than in tundra and boreal forest ecosystems – ranging from distribution shifts in wildlife to increased fire disturbance and vegetation productivity and composition. Warmer and drier conditions, for example, increase decomposition in boreal forest soils, releasing the carbon long stored as organic matter into the atmosphere as CO2. Increased fire extent, severity and seasonality all compound this problem by exacerbating a positive feedback to further warming and drying. Decreases in productivity and in surface reflectance (albedo) also act as positive feedback mechanisms, and all of these have been observed in recent decades. The need to monitor these changes is, therefore, paramount and only feasible with satellite remote sensing.

• Local Actions

  Open

  Because of the scale and long-term impact of changes in high latitudes, our work will emphasize communicating results and predictions to K-12 teachers, educators and students. WHRC is a leader in the SEARCH (Study of Environmental Arctic Change) Education and Outreach Working Group, and we have direct contact with a global network of educators with Arctic research experience, including the Student Partners Project (www.studentpartnersproject.org) and the Polaris Project (thepolarisproject.org). We will develop educational material on ongoing and predicted changes in high latitude ecosystems, for inclusion in school curricula, class room visits, meetings for science teachers, and access through the www.
  
  This material will include, but not necessarily be limited to, the following actions:
  1) mapping and monitoring the different processes on the ground that account for the observed productivity responses to climate warming and drying, and their relative importance within and between the two regions.
  2) modeling the ecosystem responses of vegetation to climatic variation between years and across decades, and predicting high latitude vegetation productivity and distribution changes under future climate change scenarios.
  3) working with local people, particularly local educators and native cultures, to learn about and act to prepare for predicted changes, and adapt to how those changes are likely to influence their traditional uses of the land and its resources.

• Region Name

  Open
  The project will focus on Alaska (interior and the North Slope) and the Cherskii region of Russia

• Partners involved in project

  Open
  The Woods Hole Research Center, the University of Alaska (Fairbanks), the Cherskii Northeast Science Station (Russia)